title: Reliability of sonographic assessment of tendinopathy in tennis elbow.
abstract: OBJECTIVE
  To assess the reliability and compute the minimum detectable change using sonographic scales to quantify the extent of pathology and hyperaemia in the common extensor tendon in people with tennis elbow.
  
  
  METHODS
  The lateral elbows of 19 people with tennis elbow were assessed sonographically twice, 1-2 weeks apart. Greyscale and power Doppler images were recorded for subsequent rating of abnormalities. Tendon thickening, hypoechogenicity, fibrillar disruption and calcification were each rated on four-point scales, and scores were summed to provide an overall rating of structural abnormality; hyperaemia was scored on a five point scale. Inter-rater reliability was established using the intraclass correlation coefficient (ICC) to compare scores assigned independently to the same set of images by a radiologist and a physiotherapist with training in musculoskeletal imaging. Test-retest reliability was assessed by comparing scores assigned by the physiotherapist to images recorded at the two sessions. The minimum detectable change (MDC) was calculated from the test-retest reliability data.
  
  
  RESULTS
  ICC values for inter-rater reliability ranged from 0.35 (95% CI: 0.05, 0.60) for fibrillar disruption to 0.77 (0.55, 0.88) for overall greyscale score, and 0.89 (0.79, 0.95) for hyperaemia. Test-retest reliability ranged from 0.70 (0.48, 0.84) for tendon thickening to 0.82 (0.66, 0.90) for overall greyscale score and 0.86 (0.73, 0.93) for calcification. The MDC for the greyscale total score was 2.0/12 and for the hyperaemia score was 1.1/5.
  
  
  CONCLUSIONS
  The sonographic scoring system used in this study may be used reliably to quantify tendon abnormalities and change over time. A relatively inexperienced imager can conduct the assessment and use the rating scales reliably.
authors.affiliation: Research Fellow, Peninsula College of Medicine & Dentistry Exeter, EX2 4SG, UK. leon.poltawski@pcmd.ac.uk
authors.forename: Leon
authors.initials: L
authors.lastname: Poltawski
authors.forename: Syed
authors.initials: S
authors.lastname: Ali
authors.forename: Vijay
authors.initials: V
authors.lastname: Jayaram
authors.forename: Tim
authors.initials: T
authors.lastname: Watson
mesh_terms: D000328:Adult; D004551:Elbow Joint / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052256:Tendinopathy / Q000000981:diagnostic imaging* / Q000209:etiology*; D013716:Tennis Elbow / Q000150:complications* / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult